Apparatus for bending hard grainless fiber sheets



Aug. 3, 1948. P. H. ESBJORNSON APPARATUS FOR BENDING-HARD GRAINLESS FIBER SHEETS 2,1942

8 Sheets-Sheet 1 Filed Dec.

1 2i" H Z'sjorrzs on APPARATUS FOR BENDING HARD GRAINLESS FIBER SHEETS Filed Dec. 2, 1942 P. H. ESBJORNSON 8 Sheets-Sheet 2 1948- P. H. EsBJoRNsoN 2,446,413

APPARATUS FOR BENDING HA RD GRAINLESS FIBER SHEETS Filed Dec. 2, 1942 8 Sheets-Sheet s \9 vifforneys P. H. ESBJORNSON Aug. 3, 1948.

' APPARATUS FOR BENDING HARD GRAINLESS FIBER SHEETS Filed Dec. 2, 1942 8 Sheets-Sheet.- 5

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Aug. 3, 1948.

P. H. ESBJORNSON APPARATUS FOR BENDING HARD GRAINLESS FIBER SHEETS Filed Dec. 2, 1942 fa SheetsSheet e In z/rzzar. Per B brrzson a; [fora/e51 M HQ I A g- 1948- P. H. ESBJORNSON ,446,413

APPARATUS FOR BENDING HARD GRAINLESS FIBER SHEETS 8 Sheets-Sheet 7 Filed Dec. 2, 1942 .27} 2/2 for Per H ijo rrzsorz Aug; 3, 1948. P. H. ESB'JORNSON APPARATUS FOR BENDING HARD GRAINLESS FIBER SHEETS Filed Dec. 2, 1942 '8 Sheets-Sheet 8 imnzorx Br 15''. ZE/arrzson M M Patented Aug. 3, 1948 APPARATUS FOR BENDING GRAINLESS FIBER SHEETS Per H. Esbjornson, Wright, Minn., assignor to The Coolerator Company, Duluth, Minn., a. corporation of Minnesota Application December 2, 1942, Serial No. 467,617

14 Claims.

This invention relates to the shaping or forming of hard, grainless fiber products made of ligno-cellulose materials, such as bag'asse, wood, and the like, and particularly to the bending of sheets of such materials.

The sheet material, with the forming or shaping of which the present invention is concerned, has been commercially produced from different raw materials such as bagasse or wood, the latter raw material being processed as taught in the Mason Patent No. 1,663,505, patented March 20, 1928, to afford a coherent grainless, hard, dense, stiff and strong product having practically all of the characteristics of natural wood, but of greater density and without grain. This product is hereinafter referred to as being a ligno-cellulose material, and is usually formed and sold in flat, smooth surfaced sheets which in most instances have been utilized in their fiat, original form. In some instances however, such sheets have formed or shaped as by bending of the sheets, but it has been possible to effect such formation only on relatively protracted radii which were too large to be useful in the construction of cabinets and the like, such as refrigerator cabinets. Hence, the primary object of this invention is to enable sheets of hard, grainles's fiber material of the aforesaid character to be bent on relatively short radii whereby sheets so bent may be employed in the construction of cabinets and the like.

Relatively large sheets of fibrous material of the aforesaid character are commercially available, and these sheets are of such size that one or more walls of a cabinet of conventional size may be conveniently formed therefrom, and by way of example it is within the purview of my invention to utilize sheets of the aforesaid character for the purpose of forming one or more Walls of a household refrigerator cabinet or the like. seams in the walls of cabinets and the like, I prefer toform a plurality of cabinet Walls from a single sheet of fibrous material of the aforesaid character and to this endI so form or bend .a sheet of material of this character that adjaa cabinet from a single sheet of material by arranging adjacent walls in angular relation with each other by bending the material at the places Whereat the corners of the cabinet are to be formed, and a further ancillary object is to so bend a sheet of material of the aforesaid char- Moreover, since it is advantageous to avoid acter that walls extending in substantially parallel relation with each, but joined to at least one interconnecting wall, may be formed from a single sheet of material of the aforesaid character.

Yet another object of the present invention is to enable a sheet of fibrous material of the aforesaid character to be heated in such a way that bending thereof may be effected and yet scorching or other damage to the material will be avoided; to insure the uniform application of pressure to a sheet of material of the aforesaid character when bending thereof is to be effected; to enable pressure to be so applied to a sheet of material of the aforesaid character that the. likelihood of damage thereto or breakage thereof will be avoided in the course of bending of the material; and to enable a sheet of material of the aforesaid character to be disposed between relatively movable surfaces of which at least one embodies a configuration like that desired to be imparted to the sheet of material upon bending thereof and to effect such bending of the material upon relative movement between such members.

Still further objects of the invention are to so relate a plurality of devices operative to effect bends ina sheet of fibrous material of the aforesaid character that When a sheet of such ma.- terial of predetermined size is arranged in the devices, bends may be formed therein in such a manner as to impart such configuration to the sheet of material that it will afford a plurality of walls of a cabinet or the like; to so arrange each of .the devices located in related positions that a sheet of material of the aforesaid character may be expeditiously positioned therein; to arrange relatively movable parts in the devices for effecting bends in a sheet of material of the aforesaid character in such a way as to enable relative operative movement to be effected therebetween and also so as to enable relative separating movement to be effected therebetween whereby a sheet of material maybe expeditiously installed therein and thereafter be retained in position to have a bending or like operation effected thereon; to effectively retain relatively separable parts in a device of the aforesaid chars acter against undesired separation; to enable selected parts of devices of the aforesaid character to be heated and to so arrange the devices that the heated parts may be kept at a desired temperature; and to automatically interrupt heating of parts as aforesaid upon completion of a bending operation and thereby prevent scorch ing or other damage to the fibrous material.

I have found that bending or like formation of a sheet of fibrous material of the aforesaid char-,

acter may be best effected when the'material is moist, and thus yet another object of this invention is to effect bending or other formation of a sheet-of material of the aforesaid character by resorting to a novelmethod for so doing entailing moistening of the sheet of material preferably at elevated temperatures and thereafter eliecting bendin of the material while. driving. the heated moisture therefrom andv which also. entails retaining the material when bent or otherwise formed to the desired configuration. for a sufficient length of time to insure that the con.- figuration imparted thereto will :be retained therein.

A still further object of the invention is to provide a novel and eflicient device of simple and; economical construction which may be utilized for thepurpose of bendingorotherwise iorming sheet material or thearoresaid character.

Qther and further objects of the present inventionwill be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustratiomshow preferred embodiments and the principle thereof and what I now considerto be the best. mode in which have contemplated applying that principle. Other embodiments of the invention embodying-the same or equivalent principle may be used. andstructural. changes may be:- made as desired by those skilled in .the art without departingifr-om the present invention and thepurview of the appended claims.

In the drawings,

Fig; 1' isa plarr view" of a device-embodying my invention;

Fig.2 is a vertical sectional view-taken substantially ontheline 2'2 on Fig. 1;

Fig. 3' is a fragmentary. plan view of certain relatively movable parts of the apparatus separated one from the other tothereby better h lustrate-the structural'fea-tures thereof;

Fig. 4 is a wiring diagram showing theelectrical connections employed in the device illustrated in'Fig. I;

Fig; 5 is a side elevational view of the device taken on the line 55 on Fig. 1;

Figs. 6 and 7 are sectional detail views taken substantially and respectively onthe lines 66 and 1'T on Fig. 5;

Fig; 8 is a fragmentary vertical detail view taken on the line -8'8'- on Fig. l anddrawn to an enlarged scale and showing certain of the opera-- tive parts of my device in alternate positions;

Fig; 9 is avertical sectional detail view takensubstantially on theline 9-9 on Fig. 8;

Figs. 10 and 11 are horizontalsectional detail views showing certain operative parts of the apparatus indifferent operative positions assumed thereby in the course of imparting predetermined bends to a sheet of fibrous material of the character referred to hereinabove Fig. 12' is a front elevational view of another embodiment ofmy invention;

Fig. 13 is a plan view of the device shown in Fig. 12;

Fig; 14 is a fragment-a1 vertical sectional view taken along the line I '4 M of Fig. 13-;

Fig; 15' is a fragmentalvertical sectional view taken along the line 45-15 of Fig. 14';

Fig. I6 is a vertical seoti'onalview taken along theline Iii-l B of Fig. 12;

Fig; 1'2 is an end: elevational view taken from the line l"l'l1'in Fig; 12;

Fig l8. is a viewsimilar to Fig- 17 and showing the parts of the machine in position {or loadingjor' unloading of a sheet; 7

Fig. 19 is a viewsimilar toFig. 17- showing the:

parts in the positions occupied at the completion era bending operation; and

Fig. 20 is: a transverse sectional View showing the parts in the same positions as in Fig. 19.

The embodiment of my invention illustrated in Figs. 1 to 11 of the accompanying drawings is particularly adapted for producing the side wall of a refrigerator cabinet of the top-opening type from. alsingle sheet of material which initially is rectangular'in' outline and which desirably is sized along the shorter edges so as to afford a side wall of the desired height and which, along the longer dimensions, is so sized that four bends are formed in the material at what are to be the upright corners of the cabinet The free ends of the sheet of. material will be brought into abutting relation desirably midway along one oftheside wallslof. themab'inet sothat. when these free edgesare joined together in any: desired way a unitary side wall for the refrigerator will be: afiorded. Moreover, the embodiment of the invention shown in Figs. 1- to 11 is arranged to produce'the outer wall ofv a refrigerator or like cabinet, but it. willbe understood that a similararrangement could be. utilized for providing the inner wall or liner of: arefrigerator or other cabinet such asiscusto marily arranged inspaced. relation with the-outer wall, whereby suitable insulation or the-like may be. arranged. between the twowalls for the pur-- poses Well understood in the art. Furthermore, while this embodiment of the invention is ar ranged to form the material so as to definevertlcally extending corners in the cabinet wall that.

is produced in'the illustrated form of the appa ratus, it will be apparent from the following. de scription that the arrangement might be. utilized to produce corners adapted to extend horizontally, and other ways in. which the illustrated forms of the inventionmay be put to use will also be apparent from the following description.

Asshown in Figs. 1 to 1-1 ofthe accompanying: drawings; the apparatus includes a base B formedinthe present instance from four strips of angle iron l5 l6; l1: and l8, Figs. 10 and1.1,,related one to'the other to afiord a substantially rectangular base. In this embodiment of the invention the strip of angleiron I? is somewhat longer than the-remainingstrips, whereby corresponding ends of the strips LG and [8- may be abutted against the flanged or inwardly disposed side oi the strip l1 and desirably the ends of the'strips l5 and 918- which abut the strips 11 are welded together. The

' strip l5is disposed to extend between the flanged or inwardly disposed; faces near the free ends of therstrips l6 and IS with the flanged side of the angle iron; t5 disposed inwardly, and the ends of the strip it: are welded or otherwise suitably secured to the. portions of' the stripsl6 and 8 against which the ends of the strips i5 are abutted. It will be understood: that while the foregoing is an advantageous way of affording a. base for the apparatus, resort could be had to other base constructions without departing from the purview of the present invention. Moreover, sinceit may'often be desirable to support the. base B in spaced relation with a floor, bench or other support on which it may be rested, angle clips C may be. bolted. or otherwise secured toabutting flanged portions of the base portion to project beneath; the flanges on the angle strips, as shown in Fig, 5,.whereby additional means for securing abutted' portions of the angle strips together are afforded, land it will be understood that in some instances where angle clips asC are-utilizedit will nOt be necessary to weld abutting ends of the angle strips together although rigidity of the base portion will be promoted if resort is had to such Welding.

The apparatus also includes a top frame T formed from angle strips i9, 20, 2| and 22, Fig. 1. These angle strips have the end portions thereof related one to the other in the manner in which the ends of the angle strips I5, I6, I! and I8 are related one to the other, and the flanges on the angle strips !9, and 2| are disposed to depend downwardly inwardly of the rectangle formed by abutting the ends of these angle strips and desirably abutting ends of the angle strips are welded one to the other to thereby afford a rigid top frame.

Posts 23, 24, and 26 are disposed at the corners of the rectangular base B and the rectangular top frame T and each post as 24, Fig. 8, is

disposed to extend upwardly from the upper flat face of an angle strip as I! to the underside of the horizontally disposed portion of an angle strip as 20 at the top of the frame, and machine screws as 21, Fig. 2, pass through the horizontally disposed portions of the angle strips of the base 13 into the posts to secure the same in position, while machine screws as 28, Fig. 2, are passed through the horizontally disposed portions of the angle strips of the frame T to pass into the posts and thereby the posts serve to support the top frame T from the base B, and the frames and posts are rigidly secured together.

Where, as in the present instance, all four Walls of a cabinet are to be formed from a single sheet of fibrous material by bending the material to thereby define the corners of the cabinet construction, it will be understood that the frames afforded by the base as B and the top frame as T will be sized, in so far as the outer dimensions thereof are concerned, to correspond to the inner dimension desired in the cabinet to be formed from such a single sheet of material. Moreover, since fibrous material that is adapted to be formed in a device of the present invention must be formed or bent on a radius, formed surfaces as FSI, F82, F83 and FSt are provided on the portions of the posts 23, 24, 25 and 26 disposed at the corners of the rectangle defined by the inner connected frames B and T and, as best. shown in Figs. 1 and 10, for example, the portions of the angle stripsof the frames B and T aligned with the formed surfaces as FSI on the posts are simi-.

larly formed. Desirably, the formed surfaces as F8! are formed on a relatively short, radius whereby relatively sharp bends may be formed in the sheet of fibrous material and in 'each instance the radius on which the formed surfaces as FS I is formed will be related to the thickness of the sheet material that is to be bent in the apparatus. For example, in an instance where the sheet material is of the nature to which Mason Patent No. 1,663,505 pertains and the sheet of material is about one-eighth inch in thickness, resort may obtained when the sheet material 'is bent there-- about for in all instances it is intended that rupture or other injury to the material will be avoided.

In order to impart a configuration to the sheet material similar to the configuration of each formed surface as FSI, means are provided to force the sheet'material into engagement with such a formed surface, and in the present instance such means are arranged to uniformly apply pressure to the sheet material, particularly at the immediate point of bending, for so to do mitigates against the likelihood of sheet material becoming damaged in the course of bending thereof.

To this end rollers RI, R2, R3 and R4 are respectively arranged for cooperation with the formed surfaces FSI FS2, PS3 and F84.

In order that each roller as R2 may be moved relative to a formed surface as F82 with which it is to cooperate, each such roller is supported in a pivotally mounted frame. By referring to Figs. 8 and 9 it will be seen that the frame for the roller R2, which corresponds to the frame provided for the other rollers, includes a bottomarm 29 and an upper arm 36 which, as'will be explained, are pivotally mounted in alignment with the vertical axis of the formed surface FS-Z. To this end the arm 29 is pivotallymounted, as indicated at P, Figs. 6 and '7, on a horizontally extending flange 31 of an angle bracket 32, Figs. 5, ;6, '7, 8 and 9, which, in a manner and for a purpose explained presently, is hingedly connected to the angle plate [1. Thus, an opening 33, Fig. 9, is provided in the arm 23 and a shouldered machine screw 34 has a cylindrical surface thereon disposed in this opening, the machine screw 34 being fitted into the horizontally ex-' tending ledge 3! of thebracket 32 and the head thereof being disposed to hold the arm 2% on the upper face of the ledge 3| of the bracket 32. The

upper arm 38. is pivotally connected to a clamp 'the machine screw being fitted into the clamp plate 35 and the head thereof being effective to retain the arm 30 in engagement with the upper surface of the clamp plate 35. 1

The arms 29 and 3&3 are of sufficient length to project well beyond the formed surface PS2 and the free ends thereof are tied together by a'bar' 38 that is extendedbetween the inwardly disposed faces of the arms 29 and 3S and which includes reduced end portions passed through aligned openings in the arms29 and 3B, the reduced end portions as 38a, Fig. '7, being screw threaded for the reception of nuts 39, Fig. 8, which, when tightened, are effective to clamp the arms 29 and all-together, whereby the arms 29 and 3B and the'bar 38 afford a frame pivotal about the vertical axis of the post 24. A handle H2 is provided on the bar 38 for a purpose explained presently.

The roller R2 includes reduced end portions as 40, Figs. 3 and 8, which are respectively mounted in openings in the arms 29 and 3!], whereby the roller R2'is connected to the arms 29 and 3!] intermediate the bar 33 and the pivotal mountings of these arms, the roller R2 being rotatable in the arms 29 and 3!}. Moreover, the roller R2 is mounted in the arms 29 and 30 in such position as to be related to the associated formed surface as FS2 and the roller is so sized and is desirably sospaced from the formed surface F82 thata sheet of material of the aforesaid character of,

predetermined. thickness may be neatly accommodated therebetween when a clamp plate,.ex-

plained. presently and associated with the roller R2, is arranged intermediate the-sheet of material. ass and the roller as R2 when the sheet of material is engaged with. the formed surface F82.

The frame including the arms 29 and 3E} and the bar 3881501110111'1851 a stop bar 41 which defines the normal at rest position of the roller R2 and which also acts to clamp the sheet as S against. the fiat surface. of the related post adiacent. to the formed surface of the post. upper end of the bar 4! is secured to a lug 42, Figs. 5' and. 8-,. that depends fromthe clamp plate 35, the rear side of the bar 41 being fast to the faceof the lug 42" by machine screws 43-", Fig. 8, or the like. The lower end of the bar M is fast to the flange A i of the angle bracket 32, which depends in: angular relation with the flange 3i thereof and which, as bestshown in- Fig. 6, projects beyond the adiacent face of. the postz l, the lower end portion 45-, Fig. 7,. of the bar H. being relieved to enable the arm 2a tobe brought into its normal at rest: positionshown in Fig. '1. The faceof the bar 4i opposite that secured. to the lug 42 and the arm 44 is recessed, as indicated at 46;.Figs. 1 and 6, so that the rollerRZ may be fitted thereinto when this roller is inv its normal at restposition which is shown in Fig. 1.

.Irrorder that asheet of fibrous material of the aforesaid character may be expeditiously fitted between a roller as R2 and aformed surface as F82, the frame of whichthe arms 28 and. and the bars 38 and H- are a part is arranged so that it may be. pivoted on the. base B: from: the hill-line position shown in Fig. 8 into the brokenline position shown. in this view. To: this end a pair of angle clips 4-? and 18* are secured to the depending portion of the angle strip H, as shown imFig. 9, to have the branches thereofspaced apart whereby the arm 44 of the angle clip 42- may- 1 be fitted therebetween. Aligned openings are provided in the arms of? the angle clips 41 and the arm 4 to receive'a bearing pin- 49. which, by-means ofa retaining pin as 50 or the like, is held against displacement from these openings; Thus the angle bracket; dzis pivotally' connected to the strip. t1 and it: may therefore be pivotedabout the pin-ta from the full-line position thereof shownin: Fig. 8 into the broken-line. position thereof shown in this view, whereupon the: frame of which the arms 29 and 3c and the bars 38: and M are a part assumes the brokenline-position shown in Fig. 8'.

g It is essential, however, when the parts are in the full-line position shown in Fig. 8, that they be held rigidly in position so as to hold the. sheetas'Sirr the-desired clamped relation to the related post, and to, this end a chamfered lug 5|, Figs. 1, 3; 5 and 8, is provided on the clamp plate 35st the inner end thereof, the inwardly disposed: face of this lug being chamfered as shownin Fig. 8. A clamp hook 52 is pivotally mounted. on the eccentric 53v that includes a bearing pin 5k that is rotatably mounted in the brackets 55 that are secured to the upper face. of the strip 20. As best shown in Figs. 1, 3 and. 8, two plates 56' have corresponding end portions thereof. interposed between the eccentric 53 and the upstanding portions of the brackets 55 and a barn die 51 is secured between the opposite ends of these. plates. and; pivot-ed awayfrom. the upper surface of; the plate 20, the eccentric :53 is so rotated that the hook end of. the clamp hook 52 is first moved The Wherr the handle 5:! is grasped.

away from the chamfered surface on the: lug 51 so that it may thereafter be pivoted upwardly, and when this end of the clamp hook- 52 is pivoted upwardly the frame of which the arms 25 and 30 are a part may be pivoted into the broken-line position in which such a frame is shownin Fig. 8; When the clamp hook 52- isin its operative relation, the roller as R2 and the stop bar 41 are held in positions such that the sheet S. is held in a firmly clamped relation to the opposed tangential surface of the post as 24.

It will be understood that a support such as. that afforded for the roller R2, and which hasbeen described hereinabove, is provided for each one of the rollers, wherefore each of these roll-- ers may be disposed. in a normal at rest position to be seated in a recess as 46, and the hook clamp- 52 associated therewith may b released so as to thereby enable the rollers to be pivoted outwardlyaway from. the formed surfaces of which they area part, and in this respect it is to be understood that the broken-line position of the roller R2 illustrated in;Fig. 8 is but an intermediate positionfor the arrangement is such. that each roller as R2 may be pivoted into right angular relationship with the formed surface with which it is to cooperate.

It is desirable that uniform pressure he appliedand maintained on a sheet of fibrous material and subsequent to the bending thereof, and to this end a thin resilientmetallic sheet as 58 is secured toeach bar 41 in. position to project from this bar .past. the formed surface associated therewith in the manner in which. the sheet 58 is shown connected to the bar 4| in Fig. 1. Each resilient sheet of material as 58 is of greater length than the formed surface as FSZ. with which it is to cooperate, and when the roller as R2 associated therewith is in its normal at rest position, the sheet of material 58 extends from the beginning. point of the formed surface in such an extent that when the roller R2 is operated in a manner tobe explained presently and a bend is formed in asheet offibrous. material, the sheet 58 will extend beyond the finishing end of the formed surface, as for example. to a point such as that whereat the sheet 58 is shown as terminating in Figs. 10 and 11. The manner. in which a sheet 58 is utilized will be explained presently, but in this respect it is to be noted that each sheet 58 is disposed intermediate each roller as R2 and a formed surface as F52 with which such roller is to cooperate, and it will. also be noted, by refer-- ence to Figs. 10 and 11, that the sheet 58 over-- lies the face of the sheet of fibrous material oprFi cgszite that engaged with the formed surface as Both heat and pressure are essential in order to efiect proper bending of a sheet of fibrous material of the character described hereinabove, and hence each post as 2'4 has a centrally extending here as 59, Fig. 2, therein and an electrically-operated heating element is mounted in each such bore, a flange as (H being provided on the element 66 to be received in an enlarged portion of the bore 58, as shown in Fig. 2, whereby the element 6.0 is suspended in the bore 59.

Thus when electrical current is supplied tothe.

element 60, it is effective to heat the post as 24 and in this respect it is to be understood that an electrical heating element as 60 is provided in each of the posts included in the present apparatus. It is desirable that each post as 24 be kept at or near a predetermined temperature and consequently I prefer to associate a thermostatic elefnent with each post that will be effective to so control the operation of the heating element as 60 associated therewith that the post as 24 will be heated to, and kept at, a desired temperature. Thus in the present instance I extend a bore 62 through the horizontally extending portion of the flange I1 into the post 24, and the temperature sensing portion 63 of a thermostat, generally indicated by 64, is extended into this bore, the thermostat 64 being screw-threaded into the horizontal flange of the angle strip H in the present instance to be supported in the bore 62. The thermostatic element will maintain the circuit closed until a predetermined temperature is reached, whereupon it will function to break the circuit, and the element is also of such a nature that it will function to close the circuit when the temperature falls below a predetermined medium, thermostatic elements of this character being well understood in the art,

In order to insure that heating of each post as 24 will be interrupted so as to thereby prevent scorching and likely damage to a sheet of fibrous material once a desired bend has been produced therein, I associate a normally closed limit switch as 65 with each post as 24. Each such limit switch includes a plunger as 66 that is effective to open the switch and thereby break the circuit established therethrough when the plunger as 66 is depressed, the plunger desirably being spring urged into an extended position so long as the switch as 55 is to remain closed. Thus in the present instance the switch 65 is mounted on the upper surface of the angle strip It in such position as to dispose the plunger 66 thereof in a location such that when the sheet of fibrous material S has been bent about the formed surface as FS2, the plunger 66 will be engaged to thereby break the circuit normally established through the switch 65. By referring to Figs. and 11, it will be seen that the switch as 65 is similarly related to each formed surface provided on the posts at the corners of my apparatus and therefore, as an incident to the completion of each bend in the sheet of fibrous material S, circuit to the heating element in the post providing the formed surface about which the material is bent is broken.

The manner in which the thermostats as 64 and the limit switches as 65 and electrical heating elements as are connected in circuit is shown in Fig. 4 and by referring there to it will be seen that a conductor 61 extends from the line wire 68 to one end of the winding included in the electrical heating unit 60. A conductor 69 extends from the other end of this winding to one terminal of the thermostat 64 while a conductor 10 leads from the other terminal of the thermostat 64 to one terminal of the switch 65,

a conductor H connecting the other terminal of the switch 65 to the other line wire 12'. As shown in Fig. 4, the heating element thermostat and limit switch associated with each of the aforesaid posts is connected between the line wires 68 and I2 in the above described manner. A switch as 13 will be provided in one of the line wires as 6 so as to enable interruption ofoperation of the heating element-s as when so desired.

As stated hereinabove, the apparatus shown in Figs. 1 to 11 of the accompanying drawings is particularly adapted to form the side walls of a refrigerator cabinet of the top-opening type and when my apparatus is to be used, a sheet of fibrous material such as that described hereinabove is selected which embodies the desired di- 10 mensions. This sheet of material when it is to be formed is immersed in water having temperature of from 130 to 150 F. fora period from about forty-five seconds to one minute to thereby moisten and somewhat heat the sheet of fibrous material, and in this respect it will be understood that the fibrousmaterial of the nature to which the present invention ertains is capable of absorbing a small percentage of moisture, particularly when immersed in relatively warm water as desired. It will be evident that higher water temperatures, up to boiling temperature may be used, but I have found that the above stated temperatures give satisfactory results where the bands to be formed in the material are not unusually sharp. In other instances the material may be conditioned for bending by a process of steaming wherein both sides of the sheet in the area which isto be bent are subjected-to steam for a period of about thirty seconds, as will hereinafter bedescribed.

Once a sheet of fibrous material has been immersed or otherwise conditioned as aforesaid, it is immediately taken to an apparatus such as that illustrated in the accompanying drawings. At this time each clamp hook as 52 of the apparatus will be released and in the present instance the sheet of fibrous material that is brought to the apparatus is disposed in engagement with the beginning ends of theformed surfaces FS2 and FS3. Moreover, the extent of the fibrous material with reference to these formed surfaces is such that when all the bends desired in the sheet of material have been completed the free edges of the sheet of material will be brought into juxtaposition along a wall opposite that afforded by the portion of the sheet material that extends be tween the formed surfaces FS2 and F83 desirably midway in this wall as shown in Fig. 11 where the juncture of the free ends of the fibrous material is indicated by J.

Once the sheet of fibrous material has been arranged in the apparatus as described, the frames carrying the rollers R2 and R3 are pivoted into a position like that in which the roller R2 is shown in Fig. 8, and the clamp hooks 52 adapted to cooperate with the frames carrying these rollers are arranged in the clamping positions thereof in which the clamp hook 52 is shown in Fig, 8. This firmly supports the rollers as R2 in predetermined relation with the formed surfaces with which they are to cooperate and it will be understood that at this time each of the rollers is seated in the recesses 46 and the strip 4| associated therewith. Moreover, it will be understood that at thi time each metallic strip as 58 will be disposed between the sheet of fibrous material and each roller as R2. Moreover, prior to the time the sheets of fibrous material are associated with the formed surfaces as F8! and FS2, the switch as 1 3 will be closed so that each electrical heating element as 60 will be effective to heat up the posts including the formed surfaces to the desired temperatures, and in this respect I have found that if the posts are maintained within a temperature range of approximately 500 F. to approximate] 900 F., satisfactory operation will result.

As soon as the rollers R2 and R3 have been clamped in effective position with a sheet of fibrous material disposed between the resilient sheets 58 and the formed surfaces with which these rollers are to cooperate, the handles as H2 and H3 associated with the rollers R2 and R3 are grasped and the rollers are caused to roll across the resilient metallic plates 58 associated therewith and since these rollers pivot about the vertical axes of the posts on which the formed surfaces as F82 and F33 are formed and since su h suriacesare also related to such vertical axes, the movement of a roller as R2 from the position thereof shown in Fig. .1 into the position thereof shown in Fig. 10 will be efiective to roll the sheet of material over the formed surface as FSZ. Inasmuch as the roller i effective on the metallic plate as 58 which in turn is effective upon the sheet of fibrous material and since the point at which the roller will be efiective through the plate on the sheet of material will be directly related to the formed surface, it is manifest that the pressure exerted by the roller as R2 on the sheet of fibrous material will be effective at the immediate point of bending, whereby the sheet of fibrous material is not subjected to undue stresses and strains.

It will be appreciated that in the course of movement of a roller as R2 from th position thereof shown in Fig. 1 into the position thereof shown in Fig. 10, t e roller advances relative to the cooperatin formed surface as F82 from the beginning o the finishing end of such surface and moreover, in the course of such movement, the sheet of resilient material 52 i eifectively applied against and held against th face of the sheet of material being bent opposite that engageable with the formedsurface.

As aroller as R2 advances from the beginning to the finishing end of a formed surface as FSZ, moisture will be driven from the sheet of material being bent primarily due to the heated condition of the formed surface. reason of the location of a limit switch as 65 rela- .tive to the finishing end of a formed surface as F82, circuit to the heatingelement associated with the formed surface will be broken as an incident to the completion of the bend in the sheet g of fibrous material. The breaking of a circuit to the heating element associated with such formed surface is effective to interrupt heating of the formed surface and in this Way scorching and like damage to the sheet of fibrous material is avoided for. as soon as the bend is completed the formed surfacecommences to'cool. Furthermore, when a roller as R2 has reached the end of a formed surface as FS 2, it is desirable that the roller be kept in this position for a period of at least about fifteen seconds, for so to do insures that the bend that has been imparted to the sheet of fibrous material will be retained therein when the sheet of fibrous material has been removed from the apparatus. Furthermore, the provision of resilient plates as 56 assists in this for such plates tend to keep pressureon the sheet of fibrous material throughout the entire bend, and this it has been found assists in insuring that the bend imparted to the fibrous material will be retained therein.

When, as in the present instance, an entire cabinet wall is to be formed from a single sheet of material as soon as the rollers as R2 and R3 have moved into the position in which these rollers are shown in Fig. 10, then the sheet of fibrous material will be extended past the beginning portion of the formed surfaces as F51 and F84 and thereupon the rollers as R! and R4 may be brought into clamping relation with the sheet of fibrous material, these rollers being clamped in this position by clamp hooks 52 in the present instance. Desirably, .the rollers as RI and R4 will :be brought into the positions in which they are shown in Fig. 10 immediately after the rollers Furthermore, by

12 R2 and R3 have attained the positions in which these rollers are shown in Fig. 10. Furthermore, immediately after this the rollers as RI and R4 are moved into the positions in which these rollers are shown in Fig. 11, and this completes for-mation of the cabinet wall which then assumes the position shown in Fig. 11 with the free ends of the sheet of fibrous material in. juxtaposed relation as indicated at J, Fig, 1. The rollers as RI and R4 are desirably retained in the positions in which they are shown in Fig. 11 for a period of about fifteen seconds to insure that the bends formed in the sheet of fibrous material upon operation of these rollers will be retained therein when the bent sheet of fibrous material is removed from the apparatus. Of course, after the elapse of such a period of timeeach of the roller frames may be released by unclamping the clamp hooks as 52 and thereupon the rollers may be pivoted away from the formed surfaces with which they cooperate, these rollers of course being related to the recesses as 36 and the bars iii associated therewith prior to the time they are again clamped in cooperative relation with the formed surfaces.

, After the rollers have been pivoted away from the formed surfaces the bent sheet of fibrous material may be lifted from the apparatus whereupon the limit switches as 65 again close circuit to the heating elements as b0, and subseouently another operation such as that described hereinabove may be repeated. It will be understood that if it were desired, for example, to impart a triangular shape to a sheet of fibrous material, then the three rollers would be required which would be related one to the other to impart the desired configuration to the sheet of fibrous material, and in this instance the various rollers and formed surfaces with which they cooperate would be related one to the other in the manner described hereinabove with reference to the arrangement enabling the sheet of material to be bent so as to afford a foursided cabinet structure.

It will also be understood that if desired the handles as H5, H2, H3 and H4 might have means associated therewith whereby they could be operated from a common point and, if desired, this could be effected by connecting flexible members to these handles and directing these flexible memhers to a common point.

The arrangement described hereinabove is one which is particularly adapted for forming a cabinet wall from a single sheet of material and is one which will enable the ends of a sheet of such material tube-brought into juxtaposed relation. It will be understood, however, that an apparatus such as that associated with any one of the hereinabove described posts could be utilized alone to form a single bond in a sheet of fibrous material and of course any desired number of devices could be related one to another to thereby afford the desired number of bends in a sheet of fibrous material.

. In the embodiment of the invention illustrated in Figs. 12 to 20 a forming machine N30 is provided which is particularly adapted for the formation-of lignot-cellulose sheets to the shape required for the construction of refrigerator doors of the character shown in the copending application of Ralph S. Schrandt, Serial No. 438,739, filed April 13, 1942, is now abandoned. The refrigerator doors disclosed in the aforesaid Schrandt application include an outer sheet of ligno -cellulose material which is rounded at its two opposite vertical edges so as to extend rearwardly, thereby to form a continuous surface across the front of the l3 door and across the two vertical side edges of the door. The forming machine I as herein shown is arranged to operate upon a sheet of lignocellulose material while the sheet is supported in a horizontal plane and in such operation the opposite edge portions of the sheet 3-2 are bent about formed surfaces so as to produce a panel or use in constructing refrigerator doors of the aforesaid character.

To this end the forming machine I00 has a rectangular base IOI formed by parallel front and rear angle iron members I02 and I03 which have angle iron spacer members I04 and I05 extended between their ends and connected rigidly thereto by means such as welded joints. A plurality of angle iron legs I 06 are secured to the respective corners of the base IOI so as to extend upwardly therefrom and an upper bed I08 is fixed upon the upper ends of the legs I06. The upper bed I08 is also formed from angle iron to provide front and rear members I09 and H0 and end members III, and these members are preferably welded to each other and to the legs I06, the arrangement being such that the flange I08 of each angle iron member of the upper bed is extended in a horizontal direction over the tops of the legs I06. Thus the flanges I08 afford sup-' porting surfaces upon which certain members of forming means may be secured, while the other flanges I08" which extend downwardly along the outer faces of the legs I06 afford surfaces upon which other elements of the forming means may be secured. I

In providing for the support of a ligno-cellulose sheet S--2 in a horizontal position, a pair of bed plates H6 and Ill are extended between and across the two end members III of the upper bed I08, the bar I I6 being disposed on one ofits edges on the tops of the frame members III adjacent to the forward edge of the upper bed I08, while the bar II! is similarly disposed relatively close to the rear edge of the upper bed I08. The bars H6 and Ill may be secured in place by means such as screws or welding, but in the present instance the. desired securing action is attained by an interconnection of elements in a manner which will hereinafter be described in detail. The bars I I6 and I II are secured together by bars H8 and H9 which extend in a direction from front to rear of the machine and are connected to the bars H6 and II! as by welding. Thus the bars H6 and Ill and the bars 8 and H9 form a unitary grid-like assembly which is rigid in character and which is supported on the members of the upper bed I08. In the present instance this grid-like frame or bed is secured in position at opposite ends by vertically extended plates I20 which are disposed midway between the front and rear edges of the machine and are secured to their respective bars II9 by screws I22 and to the respective end members of the upper bed I08 by screws I24. Since there is a plate I20 at each end of the upper bed I08, the grid-like frame is held rigidly in position. Along the tops of the rails H6 and In a plurality of bed plates I26 and I28 are secured and these plates are arranged so that their upper surfaces are in a common plane which also includes the upper surfaces of the bars H8 and H9, and hence the plates I26 and I28 afford a fiat surface for supporting a sheet S--2 of ligno-cellulose material.

It will be recalled that it is desired to shape or form the opposite edges of such a sheet so that these edges may afford side edges for a refrigerator door or the like, and to this end formed surfaces F and PS6 are mounted on the upper bed I08 in a rigid and fixed relation. to the bed sur face provided by the plates I26 and I28. The formed. surfaces FS5 and F86 are provided by tubular members or pipes in, substantially the same manner as in the other embodiment of the invention, and these tubular members are rested upon the horizontal upper flanges of the forward and rear members I09 and I I0 respectively of the upper bed I08. As shown in detail in Fig. 20 of the drawings, the cylindrical member which provides the formed surface F35 is longitudinally grooved at I30 and the forward edge of the plate I26 is substantially reduced as at I32 so as to extend into the groove I30. A plurality of screws I34 are extended through the reduced edge I32 and into the cylindrical member which provides the formed surface F85, and hence this member is held firmly in position in a predetermined relation to the plate I26. It will be observed that the plate I26 is supported at such a height that its upper surface is related tangentially to the surface of the cylindrical member so that when a lignocellulose sheet S2 is bent downwardly about the formed surface FS5, the sheet is formed on a radius such that the arcuate portion of the sheet is properly related to the main body of the sheet.

In the operation of the forming machine I00 the ligno-cellulose sheet 52 is clamped upon the bed surface provided by the plates I26 and I28 by a vertically shiftable clamping structure I which is movable from its active or clamped position of Fig. 16 to an elevated position shown in Fig. 18 s0 as to afford clearance space through which the original flat sheet S2 may be inserted and from which the finished or formed sheet maybe withdrawn. The clamping structure I40, as is best shown inFigs. 13, 15 and 16, comprises platesI46 and I48 which are positioned over and in opposed relation respectively to the plates I26 and I28, and the plates I46 and I48 are joined by transverse bars or ribs I49, Fig. 13, disposed intermediate the ends of the plates I46 and I48, and by end plates I50. Thus the clamping structure I40 is rigid in character, and this rigid struc: ture is guided for vertical movement between its inactive or retracted position of Fig. 18 and its active or clamped position of Fig. 16 by guide means acting between the stationary plate I20 and the end plates I50 of the clamping structure. Thus each of the end plates I 50 has a vertically extending elongated plate I5I secured to its inner surface as will be evident in Figs. 13 and 14 of the drawings, and guide strips I52 secured on the stationary plate I20 engage the side edges of the elongated plates I5I, thereby to guide the plates I 5| and the clamping structure I40 for vertical movement. Means is provided for actuating the clamping structure I00 between its clamped and unclamped positions and this means as herein shown includes a horizontal rock shaft I54 mounted in bearings I55 secured to the rear legs I06 of the supporting base, and arms I56 fixed to the rock shaft I54 are pivoted at I51 to the lower ends of the elongated plates I5I, this pivoted arrangement being provided by a pin and slot connection wherein the pin is fixed to the plates I5I, Fig. 14, and these pins are engaged with slots I50, Fig. 18, formed in the arms I56. Since the clamp structure I40 is of a relatively heavy construction, at least one of the arms I56 is extended rearwardly as at I59 and a counterweight I60 is adjustably secured thereto so as to substantially counterbalance the weight of the clamping structure I40. .The rock shaft I54 is in the present instance actuated by a forwardly extending foot pedal H-il pivoted at I62 on a bracket I 83 mounted on the base I I, and the rear end of the foot pedal I-6I- is connected by a link I'Mto an arm #85 fixed on the rock shaft I54. Thus when the clampingstructure Mil is to-beraised to its inactitle-position, thefoot pedal |6 l isdepressed to thereby impart the desired rocking movement to the shaft I54. When the foot pedal is released, the clamping structure I40 returns to its lower position, it being" notedthat the counterweight we may be adjusted along the arm I59 to attain this result. I

wh n the clamping structure M3 is in its lower or clamping position, the requisite clamping force is applied thereto by clamping means acting between clamping structure I49 and the stationary plates 2-0. For this purpose aclamping device H3! is provided on the clamping structure Mil adjacentto each end thereof, and each clamping device includes a shaftl6 8 extended in a direction from front to rear of the machine be tween upstanding mou-ntinglugs P69 which are provided on the plates ME and I48. Each shaft 168 has a clamp dog .I'Ill mounted thereon through the medium of an eccentric H1. The nose of the dog I l'fl is adapted to be disposed beheath-an angle bracket I'i-2 fixed on the adjacent face of the stationary plate I20, and when thedoghas been thus positioned, the shaft I68 may be rotated by an operating arm IJlS to there by-rotate the eccentric and apply clamping force which forces the dog no firmly against the angle bracket I12 and correspondingly forces the clamp structure I49 downwardly into firm clampins-relation to the sheet 82f '-It is essential that the sheet S2 be properly positionedor located in a direction transverse toxthe axes of the formed surfaces. F85v and F86", and this, must. be done before the clamping structure Mil is secured; in the position. In the present instance a shiftable gauge device I189; is provided along the forward edge of the machine, thisgauge device I88 comprising a gauge plate l:8:I; pivoted on a horizontal axis at I182 by hinge means. mounted on forwardly. projectin supporting blocks #83 secured to the upper bed 13.8 The gauge device i189 ordinarily occupies the relation shown in Fig. 1-6, but when a sheet .32 has. been placed in approximately the desired: osition, the gauge plate may be. rotated about its: axis I82 into an upstanding relation and: thogcuge plate ispressed rearwardly intoan accurately determined gauge position as shown in. 1?. This accurate gauging; position is determined by a plurality of: pins I85 which are .moimted on the gauge plate 5'81 in such a relation that. when the gauge plate is rotated to its ,ilppertpositinn the gauge pins I85 will engage; the formed surface PS5 in. a radial relation thereto. The sheet 82 may th n be manipulated so th t it; prope y enga the c use plate |;8:I- after which. the gauge device 1:80 may be withdrawn dropped to its normal position of 16-, and; the operator may then proceed with the clampin of the-sheet s2,

.f-tera sheetsflhas been clamped in: position asa-foresaid, the opposite edges thereof may: be pressed; or formed to a configuration which conforms. with the surfaces F55. and PS6, and this is; accomplished by rollers R5 andzRE which. are adapted toicooperate respectively with the formed surfaces. RS5 and The rollersRs andiBB are. supported: for operativev movement alon pathstwhich, are. concentric with. theformed surfaces with which they are to cooperate and inattaining this end the supporting means for the rollers R5 and R6 are arranged so that the rollers are moved to retracted positions at the same time when the clamping structure Hill is ele vated. For this purpose a cross arm I-9ll is secured on each of the movable plates I51, this securing action beingattained byscrews ISM as shown in Figs. 15 and 16. The cross arms I ex tend in opposite direction from the plate I5=I to points beyond the vertical planes passing re spectively through the axes of the formed surfaces F85 and F86, and supporting arms I-94 and I95 are pivoted by pivot pin-s I-96 on the opposite ends of'each of the cross arms I90. The pivots L96 are so disposed as. to lie in the respective planes which pass through theaxes of the formed surfaces RS5 and EST, and are so arranged that when the clamp structure I40 is in its lower position as shown in Fig. 15, the pivot pins I96 are disposed in a concentric relation with the axes of the related formed surfaces F85 and FSB.

The roller R5 has trunnions [98, Fig. 12; extended from its opposite ends and these trunnions are supported in bearings I99 carriedon the arm 1:94; The bearings I99 are so disposed that the lower surface of the roller R5. is disposed substan-tially'in the plane of the lower surfaceof the plate M6, and hence when theclamp structure I40- is secured in its active relation, the roller R5 will be in such a position as to apply clamping force-tothe sheet S2 toclamplthesame against the formed surface F85. In the -pres.- out construction, however, a relatively thin and bendable metal protecting plate or sheet 200 is secured on the lowersurface of the plate MB' so as to extend forwardly across the surface of a sheet S2 and beyond the edge thereof, .it having been-J found that such a protectingsheet. 200 avoids possibility of damage to the surface of the sheet S2 during the forming operation. When such a sheet 20!} is employed, the location of the axis of the roller R5 is. spaced at some- What greaterd istance from the axis of the pivot pins I198. .13. similar protecting sheet of bendable metal indicated at 2M is mounted on the plate I48: so as to extend rearwardly therefrom 3,5131! extensionuof' the lower surface thereof and the roller-R6 is. supported: on the'armsIQS by bearings 202 which are similar to the bearings I99,

Thus when a sheet S2 has been clamped in position by the clamping structure I 40; the two rollers R5? and R6 may be drawn downwardly about the axes.- defined by the pivot pins I96 to press; the sheet S2 into. the desired formed relation about the formed surfaces PS5 and F36; Preferably such actuation. of the rollers R5 and RE is accomplished in unison, and to attain this result; motion; transmitting means. is. interposed between: the arms lot: and E95 which serve to support'the rollers R5 and: R6 respectively. In .the embodiment herein shown this end is at,- tained by apair of vertical. slide plates 2110:, one ct which: ismounted at each end of, the machine, Thus asshown Figs. 13 and 1:4,,the ri ht. hand slide plate 218: is mounted for vertical} sliding increment. in the guideway which is provided on the. end plate I56 of the upper clamping structure-.. This; g-uideway. comprise-sh base p1ate.2l:l and side members. 212- which are angular in cross section. and overlie the reduced edges of theslide plate 2110i The slide plate 2H]? has. links 2:155: pivoted in similar positionsthereon and these links extend; in generally opposite directions: and are. connected: by ivotedins. .2 I56: to. the I levers or arms I94 and I95 respectively. The pivot pins 2; are disposed at the ends of the levers I94 and I95 which are opposite from the bearings I99 and 202, and hence the arms I94 and I95 are constrained, through the links 2I5 and the slide plate 2I0, to move in unison. While the desired actuating force for moving the arms I94 and I95 and the rollers R5 and R might be applied to the slide plate 250, I have, in the present instance provided a bail-like handle H on the arms I94 whereby these arms may be actuated, and the resulting motion is transmitted through the slide 2 I 0 to the arms I95.

When the forming machine 200 is in use, the formed surfaces FS5 and F86 are maintained in a heated condition by means such as-heating elements 220, Figs. 16 and 20, these heating elements in the present instance being electrical in character, and the desired temperature may be automatically maintained as in the other embodiment of the invention by thermostatic switch means. The heating elements 220 may also be controlled by cut-off switches which disconnect the current when the bending operation has been completed, as in the other embodiment of the invention.

When a sheet of ligno-cellulose material is to be operated upon by the forming machine I00, the sheet is conditioned for the forming operation by the application of heat and moisture to at least those portions of the sheet which are to undergo distortion during the forming operation. This may be accomplished by immersion of the sheet in warm water as hereinbefore described, or by a steaming process. In such a steaming process I preferably utilize steam pipes disposed opposite both faces of the areas which are to be bent or distorted, and openings are provided in the steam pipes to discharge the steam against the surfaces of the sheet. Preferably the steam pipes have housings thereabove which engage the surfaces of the sheet to confine the steam to the desired areas of such surfaces, and after steam has been applied to the sheet for a period of from to 30 seconds, the housings are separated to permit withdrawal of the sheet. The sheet is then transferred to the machine I00, the clamping structure I40 being elevated by the pedal I6! to its elevated position of Fig. 18. The sheet S2 is inserted in a rearward direction so as to be disposed between the lower bed I08 and the clamping structure I40, and after the sheet has been accurately posi tioned by the gauge device I80, the clamp structure M0 is shifted to its lower position and clamping force is applied through by the clamp devices I61. 7 The rollers R5 and R6 are then operated in unison through actuation of the handle H5, and the sheet is gradually bent about and pressed against the formed surfaces FS? and F86. When the rollers R5 and R6 have reached their lower positions, as shown in Figs. 19 and 20, the forming operation is complete, but the rollers are maintained in this position so as to maintain the sheet S2 under pressure throughout-the formed portion for a short period of about 15 seconds, it being noted that the bendable plates or sheets 200 and I cooperate with the rollers R5 and R6 during this period to apply pressure to the formed surfaces of the sheet. When the rollers R5 and R5 are returned to their upper positions of Fig. 16 after a forming operation as aforesaid, the sheet S2 will retain the form to which it has been bent,

.and the clamping devices I61 may therefore be released and the clamping structure I40 may be ele-.

vated to the position of Fig. 18, thereby to provide 18 clearance space-through which they formed sheet S2 may be withdrawn.

From the foregoing it will be apparent that the present invention enables ligno-cellulose sheets and the like to be conveniently and accurately formed so as to afford relatively sharp or short radius bends therein, thereby to enable such sheets to be utilized as structural elements of cabinets, refrigerators and the like. Such formation-of the ligno-cellulose sheets is accomplished under this invention without breaking or cracking .of the surfaces of the sheets, and hence these formed sheets may be used as the outer casing members to afford finished and unbroken or unseamed surfaces for such cabinets.

Hence, while I have illustrated and described preferred embodiments of my invention, it isto be understood that these are capable of variation and modification and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

I claim:

1. In a machine for forming relatively shortradius bends in ligno-cellulose and like sheets, means providing a formed surface of arcuate shape having a radius equal to the desired radius of the inner surface of the bend to be formed in aligno -cellulose and like sheet, means providing a clamping surface merging with said formed surface in tangential relation thereto, a clamping member for clamping such a sheet against said clamping surface with a portion of the sheet extending beyond said clamping surface and in a tangential relation to said formed surface, and

means carried by said clamping member and of the inner surface of the bend to be formed-in a lignoecellulose and like sheet, means providing a clamping surface merging with said formed surface in tangential relation thereto, a clamping member for clamping such a sheet against said clamping surface with a portion ofthe sheet extending beyond said clamping surface and in a tangential relation to said formed surface, a pressure roller, and means supporting said pressure roller on said clamping member for operative movement along a path centered. on the axis of said formed surface to press the extending portion of the sheet into engagement With said formed surface.

. 3. In a machine for forming relatively shortradius bends in ligno-celluloseandlike sheets, means providing a formed surface of arcuate shape having a radius equal to the desired radius of the inner surface of the bend to be formed in a ligno-cellulose and like sheet, means providing 7 a clamping surface merging with said formed surface in tangential relation thereto, a clamping member for clamping such a sheet against said clamping surface with a portion of the sheet extending beyond said clamping surface and in a tangential relation to said; formed surface, means for heating said formed surface to'substantially a predetermined temperature, a pressure roller,

and means supporting said pressure roller on said clamping member for operative movement along a path centered on the axis of said formed surface 2 gown 13 19 to press theextending portion of thc sheet-into engagement with said forme'd surface.

'4. In a machine 'ior forming relatively shortradius bends :in ligno-celiulose and "like sheets, means providing a formed surface of arcuate shapehaving-a radius equal to the desired radius of the inner surface of a bendto' be formed in a ligno-cellulose andlike sl'ieet, means-providing a clamping-surfacemerging with said formed surface in tangential relation thereto, a clamping member for clamping such a sheet against said clamping surface with a portion of the-sheet extendingbeyond said clampingsurface andin a tangential relation to said formed surface, a pair of arms pivoted on said clamping member for movement about an axis which is disposed on'the axis of said arcuate formed surface when said clamping member is'in clamping relation to said clamping surface, and a pressure-roller supported on-said arms in spaeedrelation to the pivotal axis thereof for operative movement along'a path centeredon the axis of said formed surface-to press the extending portion of the sheet into engagement with said formed surface.

*In a machine for forming 'relativelyshortradius bends in ligno-cellulose and like sheets, means providing a formed surface of arcuate shape having aradius equalto the desired radius of the-inner surfaceof the 'bend'to beformed in alig'no-cellulose and'like s-heet, means-providing a -clamping surface -merging "with said formed surfaceintangential relation thereto, a clamping member for clamping sucha-sheet againstsaid clamping surface with-a portionof-the s'h'eetex- "tending beyond said clamping *sur'face'and 'in a tangential relation to said formed surface, means carriedbysaidclamping member and movable relative thereto to bend the extending portion of such-a-sheet into contact-with said formed surface, and means for heating said 'forme'd surface while the'sheet is being thusberit into contact therewith.

6. 'In a machin'e for forming relatively shortra'dius bends in ligno-cellulose "and 'like sheets, means providing a formed surface of 'arcuate shape-having a-radius'equal to thedesired radius ofthe inner surface of the bend to'be formed'i-n a ligno-cellulose and like-sheet, means providing -aclamping surface mergingwith said formed-sur- 'face in tangental relation thereto, a clamping member'for clamping such a sheet against said clamping surface with a portion of-thesheet extending beyond said clamping surface and ma tangential relation 'to said formed surface, arelatively thin and bendable sheet carried on said clamping member in position to engagesuch an extending portion of asheet when'said clamping member is in clamping position, a pressure roller, and means supporting said pressure 'ro'ller on said clamping "member for operative movement aionga path centered on the axis of said formed surface to move said roller over said bendable sheetto press theextending portion of the'lignocellulose or like sheet into engagement with said formed surface.

'7. Ina machine for forming relatively short- -radius bends in ligno-celulose and like sheets, means providing a formed surface of arcuate shape having-a radius equal to the desired radius of the inner surface of the bend to be formed in a ligno-cellulose and like sheet, means providing a clamping surface merging with said formed surface in tangential relation thereto, a clamping :member for clamping such a sheet against said clamping surface with a portion of'thesheet extending beyond said clamping surface and in "a tangential relation to said formed surface, a pair of arms pivoted on said clamping-memberfor movement about an axis which isdisposed on the axis of said arcuate formed surface when said clamping member is in clamping relation 1 to said clamping surface, a-pressureroller supported on said arms in spaced relation to the pivotal axis thereof for operative movement along a path centered on the-axis of said formed surface topress the extending portion of the sheet into engagement with said formed surface, and a-pro'tective sheet of bendable metal carried by said clamping member in position to'transmi-t bending force from said roller to the extending portion of the ligno-cellulose orlike sheet.

"8. In a machine for forming relatively shortradius bends in ligno-cellulose and like-sheets-a pair of elongated members supported for relative clamping-and separating movement and between which a ligno-cellulose or like sheet may be clamped, means rigidly associated with -one of said members andproviding a formed surf'aceof arcuateshape' having aradius equal to the desired radius of the inner surface of the bend to be formed in a ligno-cellulose and like sheet, a-pair or arms pivoted onthe other of said members'for movement about an axis which is disposed on the axis of said 'arcuate formed surface when said elongated members are insaid clamping'relation, and a pressure roller supported on said arms in "spaced relation 'to the I pivotal axis thereof "for uperative movement 'along a path'cente'red'on the axis of saidformed 'suifaee'to press an extending portion of the sheet into engagement with-said formed surface.

9. In am'achine 'for shaping a single sheet of ligno-cellulose or like material to form a foursided wall assembly having the walls thereof 3 oined by'integral rounded'corners, a plurality of elongatedposts, each having a rounded outer corner'surface'afiordlng a formed surface conforming-with the desired form of the'inner surfaces to be formed, means supporting said posts 1 in a rigid and-parallel relation such that said rounded outer corners of the posts are located in positions conforming to'the locations'of theizmer surfaces of the rounded corners to be formed, an clongated carrier structure allocated to each post, each carrier structure including an elongated clampbar, a pairof arms 'pivotedon a common axis on the-clamp bar adjacent opposite ends of the bar, and a pressure roller mounted between the pair of arms, means pivoting each clamp bar adjacent to one end of the related post for-movemerit of the'carrier structure from an ou't-of-theway position substantially perpendicular to the related post to an active'cla'mping position wherein said bar is parallel to the post to which it is allocated, the pivoted axis of the pivoted arms being concentric with the axis of the formed surfaceof the related post when the clamp bar is in its active clamping position, and means for securing said clamp bars in said active clamping positions.

10. In a machine for shaping a single shee'tof "ligno-cellulose or like material to form a foursided Wall assembly having the walls thereof joined by integral rounded corners, a base, aplurality of elongated posts extended upwardly from said base at points located at the corners of a rectangle, said posts having rounded outer corners affording formed surfaces conforming to the desired form of the inner surfaces of the rounded corners to b formed, an elongated carrier structure allocated to each post, each carrier structure including an elongated clamp bar, a pair of arms pivoted on a common axis on the clamp bar adjacent opposite ends of the bar, and a pressure roller mounted between the pair of arms, means pivoting the lower end of each clamp bar on said base for movement of the carrier structure from a substantially horizontal out-of-the-way position to an active clamping position wherein said bar is parallel to the post to which it is allocated, the pivotal axis of the pivoted arms being concentric with the axis of the formed surface of the related post when the clamp bar is in its active clamping position, and means for securing said clamp bars in said active clamping positions.

11. In a machine for shaping a single sheet of ligno-cell-ulose or like material to form a foursided wall assembly having the walls thereof joined by integral rounded corners, a base, a plurality of elongated posts extended upwardly from said base at points located at the corners of a rectangle, said posts having rounded outer corners affording formed surfaces conforming to the desired form of the inner surfaces of the rounded corners to be formed, an elongated carrier structure allocated to each post, each carrier structure including an elongated clamp bar, a pair of \arms pivoted on a common axis on the clamp bar adjacent opposite ends of the bar, and a pressure roller mounted between the pair of arms, means pivoting the lower end of each clamp bar on said base for movement of the carrier structure from a substantially horizontal out-of-the-way position to an active clamping position wherein said bar is parallel to the post to which it is allocated, the pivotal axis of the pivoted arms being concentric with the axis of the formed surface of the related post when the clamp bar is in its active clamping position, means for securing said clamp bars in said active clamping positions, individual means for heating said posts to normally maintain the same within a predetermined temperature range, and individual means associated with each post for rendering the heating means of the respective posts inoperative when a sheet has been bent around the formed surface of a post.

12. In a machine for shaping a sheet of lignocellulose and like material to provide a wall panel having integral rounded corners at opposite edges thereof, a stationary supporting bed upon which such a sheet may be positioned, a pair of elongated forming elements each having an arcuate formed surface thereon and extending longitudinally thereof, means supporting said forming elements in a predetermined parallel relation along opposite edges of said bed so that the formed surfaces thereof are related to each other in the relation desired for the inner surfaces of the rounded corners of the wall panel that is to be formed, a clamping structure mounted in opposed relation to said bed for clamping portions of such a sheet against said bed and against said forming elements adjacent to said formed surfaces, and pressure means mounted on said clamping structure and operable to bend projecting edge portions of such a sheet into engagement with said formed surfaces.

13. In a machine for shaping a sheet of lignocellulose and like material to provide a wall panel having integral rounded corners at the opposite edges thereof, a stationary supporting bed upon which such a sheet may be positioned, a pair of elongated forming elements each having an arcuate formed surface thereon and extending longitudinally thereof, means supporting said forming elements along opposite edges of said bed and in a predetermined parallel relation .to each other such that the formed surfaces thereof are related to each other in the relation desired for the inner surfaces of the rounded corners of the connected walls that are to be formed, a clamping structure mounted for movement into a clamping relation to said bed for clamping portions of such a sheet against said bed and against the forming elements adjacent to said formed surfaces, and individual pressure rollers for cooperation with the respective formed surfaces, and means mounted on said clamping structure for moving said pressure rollers in unison along paths concentric with their respective formed surfaces to press extending edge portions of the sheet against the related formed surfaces.

14. In a machine for shaping a sheet of lignocellulose and like material to provide a wall panel having integral rounded corners at the opposite edges thereof, a stationary supporting bed upon which such a sheet may be positioned, a pair of elongated forming elements each having an arcuate formed surface thereon and extending longitudinally thereof, means supporting said forming elements along opposite edges of said bed and in a predetermined parallel relation to each other such that the formed surfaces thereof are related to each other in the relation desired for the inner surfaces of the rounded corners of the connected walls that are to be formed, a clamping structure mounted for movement into a clamping relation to said bed for clamping portions of such a sheet against said bed and against the forming elements adjacent to said formed surfaces, and individual pressure rollers for cooperation with the respective formed surfaces, a gauge device mounted on said bed for locating a sheet thereon, and means mounted on said clamping structure for moving said pressure rollers in unison along paths concentric with their respective formed surfaces to press extending edge portions of the sheet against the related formed surfaces.

P. H. ESBJORNSON.

REFERENCES CITED The following references are of record in the I file of this patent:

UNITED STATES PATENTS Number Name Date 92,187 Hamm July 6, 1869 784,471 Church Mar. 7, 1905 843,854 Waterman Feb. 12, 1907 1,508,866 Williams Sept. 16, 1924 1,606,271 Stratford Nov. 9, 1926 1,642,657 Frick Sept. 13, 1927 1,754,549 Elliott Apr. 15, 1930 1,760,288 Stevens May 27, 1930 1,769,570 Groehn et al July 1, 1930 1,856,319 Cooper May 3, 1932 2,289,685 Schoen July 14, 1942 2,382,807 Nobles Aug. 14, 1945 FOREIGN PATENTS Number Country Date 650,680 France Sept. 25, 1928 

